Featured Research

from universities, journals, and other organizations

Gap Junction Protein Vital To Successful Pregnancy, Researchers Find

Date:

September 15, 2008

Source:

University of Illinois at Urbana-Champaign

Summary:

Researchers studying a critical stage of pregnancy -- implantation of the embryo in the uterus -- have found a protein that is vital to the growth of new blood vessels that sustain the embryo. Without this protein, which is produced in higher quantities in the presence of estrogen, the embryo is unlikely to survive.

Share This

Deleting the Cx43 gene in the uterus immediately after pregnancy in mice dramatically reduced blood vessel growth and in most cases prevented successful pregnancy. The image on the left shows normal blood vessel growth in the mouse uterus following pregnancy. On the right, a uterus lacking Cx43.

Credit: Photo by Mary J. Laws

Researchers studying a critical stage of pregnancy – implantation of the embryo in the uterus – have found a protein that is vital to the growth of new blood vessels that sustain the embryo. Without this protein, which is produced in higher quantities in the presence of estrogen, the embryo is unlikely to survive.

Related Articles

This is the first study to detail the mechanism by which the steroid hormone estrogen spurs cell differentiation and blood-vessel growth in the uterus during pregnancy, the researchers report.

The findings, from researchers at the University of Illinois, Emory University, Baylor College of Medicine and New York University, appear in the journal Development.

Connexin 43 (Cx43) belongs to a family of proteins that form junctions between cells that regulate the flow of ions and small signaling molecules from cell to cell. At the time of embryo implantation, this gap junction protein is essential to the rapid growth of new blood vessels needed to support the development of the embryo and allow it to implant in the uterine wall, the researchers discovered.

The researchers chose to study Cx43 after analyzing genes that are activated in the presence of estrogen in uterine cells. They found that Cx43 was prominent among the genes whose expression was increased in cells after exposure to estrogen.

University of Illinois veterinary biosciences doctoral student Mary Laws studied the role of Cx43 in pregnant mice and in human endometrial cells. By deleting the Cx43 gene in the uterus immediately after pregnancy in mice, a technique developed by researchers at Baylor, Laws was able to reliably prevent implantation of the embryo in the uterus.

In human endometrial cells (provided by co-author Robert Taylor of Emory University), Cx43 enhanced the differentiation of cells that make up the stromal tissue of the uterus. These cells produce factors that promote the growth of new blood vessels.

One of the factors secreted by the endometrial cells, vascular endothelial growth factor (VEGF), is essential to angiogenesis. In the absence of Cx43, Laws found, the cells failed to differentiate or to produce enough VEGF to spur blood vessel growth.

"The formation of these new blood vessels is extremely critical for embryonic growth at this stage of pregnancy, when the embryo has begun to invade into the uterine tissue, but has yet to make a connection to the placenta where it ultimately gets its nutrients," said Illinois veterinary biosciences professor Indrani Bagchi, corresponding author on the study. "I think this is the first animal model that shows that disruption of one particular molecule or gene leads to a defect in uterine angiogenesis."

The findings have important implications for early pregnancy loss and female infertility, she said.

"A fundamental aspect of female reproductive biology is how these hormones signal in uterine tissue in order to support the pregnancy," said molecular and integrative physiology professor Milan Bagchi, an author on the study. "One of our major goals is to identify the genes that are regulated by estrogen and progesterone precisely at the time when the embryo implants in the uterine wall."

"Connexin 43 has been shown to be in the uterus in many animal systems – cows and pigs and rodents and humans," Laws said. "But this is the first time that it's been shown to be critical for pregnancy."

This research was sponsored by the recently established Center for Research in Reproduction and Infertility, which is funded by the National Institute of Child Health and Human Development. Based at the U. of I., the center also draws expertise from Emory University Medical School and Baylor College of Medicine.

Featured Research

Mar. 31, 2015  Researchers have illuminated an important distinction between mice and humans: how human livers heal. The difference centers on a protein called PPAR alpha which activates liver ... full story

Mar. 31, 2015  Researchers have recorded the first direct observations of the micro-scale mechanisms behind the ability of skin to resist tearing. The results could be applied to the improvement of artificial skin, ... full story

Mar. 31, 2015  Fewer than half of the physicians trained in the United States in 2013 received formal education or training on the subject of exercise, according to new research. "There are immense medical benefits ... full story

Mar. 31, 2015  Memory and as well as connections between brain cells were restored in mice with a model of Alzheimer's given an experimental cancer drug, researchers report. "With this treatment, cells under ... full story

Mar. 31, 2015  Increasing state alcohol taxes could prevent thousands of deaths a year from car crashes, say researchers, who found alcohol-related motor vehicle crashes decreased after taxes on beer, wine and ... full story

Mar. 31, 2015  Alcoholism takes a toll on every aspect of a person's life, including skin problems. Now, a new research report helps explain why this happens and what might be done to address it. "The clinical ... full story

Mar. 31, 2015  A new population of 'memory' immune cells has been discovered by scientists, throwing light on what the body does when it sees a microbe for the second time. This insight, and others like it, will ... full story

Mar. 31, 2015  Coronary heart disease and stroke, two of the leading causes of death in the United States, are diseases associated with heightened platelet reactivity. A new study in humans suggests an underlying ... full story

Mar. 31, 2015  A new study had researchers seeking answers to why the therapeutic benefit afforded by SSRIs was so limited in children and teenagers. If researchers can uncover the biological mechanisms preventing ... full story

Featured Videos

Solitair Device Aims to Takes Guesswork out of Sun Safety

Reuters - Innovations Video Online (Mar. 31, 2015)  The Solitair device aims to take the confusion out of how much sunlight we should expose our skin to. Small enough to be worn as a tie or hair clip, it monitors the user&apos;s sun exposure by taking into account their skin pigment, location and schedule. Matthew Stock reports.
Video provided by Reuters

Soda, Salt and Sugar: The Next Generation of Taxes

Washington Post (Mar. 30, 2015)  Denisa Livingston, a health advocate for the Dinι Community Advocacy Alliance, and the Post&apos;s Abby Phillip discuss efforts around the country to make unhealthy food choices hurt your wallet as much as your waistline.
Video provided by Washington Post

S. Leone in New Anti-Ebola Lockdown

AFP (Mar. 28, 2015)  Sierra Leone imposed a three-day nationwide lockdown Friday for the second time in six months in a bid to prevent a resurgence of the deadly Ebola virus. Duration: 01:17
Video provided by AFP

Related Stories

July 17, 2014  A crucial molecular key to healthy embryo implantation and pregnancy has been discovered in a study that may offer new clues about the medical challenges of infertility/subfertility, abnormal ... full story

Feb. 6, 2014  Researchers have discovered how an ‘entrance exam’ set by the womb determines if the implantation of an embryo is successful; potentially a milestone for advances in pregnancy ... full story

Jan. 21, 2013  Scientists have developed a new tool, a mathematical model to be exact, to help in the selection of embryos for transfer in fertility treatments. The model is especially useful for transfers of ... full story

Sep. 21, 2012  Adding a missing protein to infertile human sperm can "kick-start" its ability to fertilize an egg and dramatically increase the chances of a successful pregnancy, scientists have ... full story

ScienceDaily features breaking news and videos about the latest discoveries in health, technology, the environment, and more -- from major news services and leading universities, scientific journals, and research organizations.